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United States Patent 5,527,986
Weber June 18, 1996
Inbred corn line PHTD5

Abstract

According to the invention, there is provided an inbred corn line, designated PHTD5. This invention thus relates to the plants and seeds of inbred corn line PHTD5 and to methods for producing a corn plant produced by crossing the inbred line PHTD5 with itself or with another corn plant. This invention further relates to hybrid corn seeds and plants produced by crossing the inbred line PHTD5 with another corn line or plant.

Inventors: Weber; Gerhart P. (Moorhead, MN)
Assignee: Pioneer Hi-Bred International, Inc. (Des Moines, IA)
Appl. No.: 186193
Filed: January 24, 1994

Current U.S. Class: 800/274; 47/DIG.1; 435/412; 800/320.1
Intern'l Class: A01H 005/00; A01H 004/00; A01H 001/00; C12N 005/04
Field of Search: 800/200,205,250,DIG. 56 47/58.03,58.05,DIG. 1 435/240.4,145.49,172.3

References Cited
U.S. Patent Documents
4812599Mar., 1989Segebart800/200.
Foreign Patent Documents
160390Nov., 1985EP.


Other References

Conger, B. V., et al., (1987)"Somatic Embryogenesis From Cultured Leaf Segments of Zea Mays", Plant Cell Reports, 6:345-347.
Duncan, D. R., et al. (1985) "The Production of Callus Capable of Plant Regeneration From Immature Embryos of Numerous Zea Mays Genotypes", Planta, 165:322-332.
Edallo, et al. (1981) "Chromosomal Variation and Frequency of Spontaneous Mutation Associated with in Vitro Culture and Plant Regeneration in Maize", Maydica, XXVI: 39-56.
Green, et al., "Plant Regeneration From Tissue Cultures of Maize", Crop Science, vol. 15, pp. 417-421.
Green, C. E., et al. (1982) "Plant Regeneration in Tissue Cultures of Maize" Maize for Biological Research, pp. 367-372.
Hallauer, A. R. et al. (1988) "Corn Breeding" Corn and Corn Inmprovement, No. 18, pp. 463-481.
Meghji, M. R., et al. (1984). "Inbreeding Depression, Inbred & Hybrid Grain Yields, and Other Traits of Maize Genotypes Representing Three Eras", Crop Science, vol. 24, pp. 545-549.
Phillips, et al. (1988) "Cell/Tissue Culture and In Vitro Manipulation", Corn & Corn Improvement, 3rd Ed., ASA Publication, No. 18, pp. 345-349 & 356-357.
Poehlman (1987) Breeding Field Crop. AVI Publishing Co., Westport, Ct., pp. 237-246.
Rao, K. V., et al., "Somatic Embryogenesis in Glume Callus Cultures", Osmania University, Hyberabad, India.
Sass, John F. (1977) "Morphology", Corn & Corn Improvement, ASA Publication. Madison, Wisconsin, pp. 89-109.
Songstad, D. D. et al. (1988) "Effect of ACC (1-aminocyclopropane-1-carboxyclic acid), Silver Nitrate & Norbonadiene on Plant Regeneration From Maize Callus Cultures", Plant Cell Reports, 7:262-265.
Tomes, et al. "The Effect of Parental Genotype on Initiation of Embryogenic Callus From Elite Maize (Zea Mays L.) Germplasm", Theor. Appl. Genet., vol. 70, pp. 505-509.
Troyer, et al. (1985) "Selection for Early Flowering in Corn: 10 Late Synthetics", Crop Science, vol. 25, pp. 695-697.
Umbeck, et al. "Reversion of Male-Sterile T-Cytoplasm Maize to Male Fertility in Tissue Culture", Crop Science, vol. 23, pp. 584-588.
Wright, Harold (1980) "Commercial Hybrid Seed Production", Hybridization of Crop Plants, Ch. 8: 161-176.
Wych, Robert D. (1988) "Production of Hybrid Seed", Corn and Corn Improvement, Ch. 9, pp. 565-607.

Primary Examiner: Benzion; Gary
Claims


What is claimed is:

1. Inbred corn seed designated PHTD5 and having the genotype of ATCC Accession No. 97373.

2. A corn plant and it parts produced by the seed of claim 1.

3. A tissue culture of regenerable cells of a plant of PHTD5, seeds of which have been deposited as ATCC Accession No. 97373, wherein the tissue culture regenerates plants having the genotype of PHTD5.

4. A tissue culture according to claim 3, the tissue culture selected from the group consisting of leaves, pollen, embryos, roots, root tips, anthers, silk, flowers, kernels, ears, cobs, husks and stalks, and cells and protoplasts thereof.

5. A corn plant regenerated from the tissue culture of claim 3 and having a genotype capable of expressing all the physiological and morphological characteristics of PHDT5.

6. A process to produce F.sub.1 hybrid corn seed which gives rise to a hybrid corn plant having alleles that, when expressed, contribute to hybrids having high yield and low grain moisture at harvest, compared to similarly adapted hybrids, comprising the steps of:

a) planting, in pollinating proximity, seeds of two parental lines, one of the parental lines being PHTD5, the seed of which have been deposited as ATCC Accession No. 97373, and the other parental line having a genotype different from PHTD5;

(b) cultivating corn plants resulting from said planting;

(c) preventing pollination formation by the plants of one of the parental lines,

(d) allowing natural cross pollinating to occur between said parental inbred lines; and

(e) harvesting seeds produced by the plains which do not form pollen.

7. F.sub.1 hybrid seed produced by the process of claim 6.

8. Hybrid seed produced by F.sub.1 hybrid combination of plants of inbred corn seed designated PHTD5 and having ATCC Accession No. 97373 and plants of a parental line having a genotype different from PHTD5.

9. Hybrid plants grown from seed of claim 8.

10. A tissue culture of regenerable cells of a corn plant grown from seed produced by sexually crossing inbred corn line PHTD5, the seed of which have been as deposited ATCC Accession No 97373, and a parental line having a genotype different from inbred corn line PHTD5.

11. An F.sub.1 hybrid corn seed, one half of the nuclear genotype of which is contributed by inbred corn line PHTD5.

12. An F.sub.1 hybrid corn plant grown from the seed of claim 11.
Description


FIELD OF THE INVENTION

This invention is in the field of corn breeding, specifically relating to an inbred corn line designated PHTD5.

BACKGROUND OF THE INVENTION

Plant Breeding

Field crops are bred through techniques that take advantage of the plant's method of pollination. A plant is self-pollinated if pollen from one flower is transferred to the same or another flower of the same plant. A plant is cross-pollinated if the pollen comes from a flower on a different plant.

Corn plants (Zea mays L.) can be bred by both self-pollination and cross-pollination techniques. Corn has separate male and female flowers on the same plant, located on the tassel and the ear, respectively. Natural pollination occurs in corn when wind blows pollen from the tassels to the silks that protrude from the tops of the incipient ears.

The development of a hybrid corn variety involves three steps: (1) the selection of plants from various germplasm pools; (2) the selfing of the selected plants for several generations to produce a series of inbred lines, which, although different from each other, breed true and are highly uniform; and (3) crossing the selected inbred lines with unrelated inbred lines to produce the hybrid progeny (F.sub.1). During the inbreeding process in corn, the vigor of the lines decreases. Vigor is restored when two unrelated inbred lines are crossed to produce the hybrid progeny. An important consequence of the homozygosity and homogeneity of the inbred lines is that the hybrid between any two inbreds will always be the same. Once the inbreds that give a superior hybrid have been identified, the hybrid seed can be reproduced indefinitely as long as the homogeneity of the inbred parents is maintained.

The objective of commercial maize inbred line development programs is to develop new inbred lines that combine to produce high grain yields and superior agronomic performance in hybrid combination. The primary trait breeders seek is yield. However, other major agronomic traits are of importance in hybrid combination and have an impact on yield or otherwise provide superior performance in hybrid combinations. Such traits include percent grain moisture at harvest, relative maturity, resistance to stalk breakage, resistance to root lodging, grain quality, and disease and insect resistance. In addition the lines per se must have acceptable performance for parental traits such as seed yields, kernel sizes, pollen production, all of which affect the ability to provide parental lines in sufficient quantity and quality for hybridization. Traits have been shown to be under genetic control and many if not all of the traits are affected by multiple genes. Thus, to be selected as an inbred line, the inbred must be able to combine such that the desired traits are passed to the hybrid and also be able to satisfy production requirements as a parental line.

Pedigree Breeding

The pedigree method of breeding is the mostly widely used methodology for new inbred line development.

In general terms this procedure consists of crossing two inbred lines to produce the non-segregating F.sub.1 generation, and self pollination of the F.sub.1 generation to produce the F.sub.2 generation that segregates for all factors for which the inbred parents differ. An example of this process is set forth below. Variations of this generalized pedigree method are used, but all these variations produce a segregating generation which contains a range of variation for the traits of interest.

EXAMPLE 1

Hypothetical Example of Pedigree Breeding Program

Consider a cross between two inbred lines that differ for alleles at five loci.

The parental genotypes are: 

    ______________________________________
    Parent 1
           A     b     C    d   e   F/A   b   C   d    e   F
    Parent 2
           a     B     c    D   E   f/a   B   c   D    E   f
    ______________________________________


the F.sub.1 from a cross between these two parents is: 

    ______________________________________
    F.sub.1
         A     b      C   d    e   F/a   B   c    D   E   f
    ______________________________________


Selfing F.sub.1 will produce an F.sub.2 generation including the following genotypes: 

    ______________________________________
    A    B     c      D        E   f/a   b   C    d   e    F
    A    B     c      D        e   f/a   b   C    d   E    F
    A    B     c      D        e   f/a   b   C    d   e    F
                          .
                          .
                          .
    ______________________________________


The number of genotypes in the F.sub.2 is 3.sup.6 for six segregating loci (729) and will produce (2.sup.6)-2 possible new inbreds, (62 for six segregating loci).

Each inbred parent which is used in breeding crosses represents a unique combination of genes, and the combined effects of the genes define the performance of the inbred and its performance in hybrid combination. There is published evidence (Smith, O. S., J. S. C. Smith, S. L. Bowen, R. A. Tenborg and S. J. Wall, TAG 80:833-840 (1990)) that each of these lines are different and can be uniquely identified on the basis of genetically-controlled molecular markers.

It has been shown (Hallauer, Arnel R. and Miranda, J. B. Fo. Quantitative Genetics in Maize Breeding, Iowa State University Press, Ames Iowa (1981)) that most traits of economic value in maize are under the genetic control of multiple genetic loci, and that there are a large number of unique combinations of these genes present in elite maize germplasm. If not, genetic progress using elite inbred lines would no longer be possible. Studies by Duvick and Russell (Duvick, D. N. Maydica 37:69-79 (1992); Russell, W. A. Maydica XXIX:375-390 (1983)) have shown that over the last 50 years the rate of genetic progress in commercial hybrids has been between 1 and 2% per year.

The number of genes affecting the trait of primary economic importance in maize, grain yield, has been estimated to be in the range of 10-1000. Inbred lines which are used as parents for breeding crosses differ in the number and combination of these genes. These factors make the plant breeder's task more difficult. Compounding this is evidence that no one line contains the favorable allele at all loci, and that different alleles have different economic values depending on the genetic background and field environment in which the hybrid is grown. Fifty years of breeding experience shows that there are many genes affecting grain yield and each of these has a relatively small effect On this trait. The effects are small compared to breeders' ability to measure grain yield differences in evaluation trials. Therefore, the parents of the breeding cross must differ at several of these loci so that the genetic differences in the progeny will be large enough that breeders can develop a line that increases the economic worth of its hybrids over that of hybrids made with either parent.

If the number of loci segregating in a cross between two inbred lines is n, the number of .unique genotypes in the F.sub.2 generation is 3.sup.n (Example 2) and the number of unique inbred lines from this cross is {(2.sup.n)-2}. Only a very limited number of these combinations are useful. Only about 1 in 10,000 of the progeny from F.sub.2 's are commercially useful.

By way of example, if it is assumed that the number of segregating loci in F.sub.2 is somewhere between 20 and 50, and that each parent is fixed for half the favorable alleles, it is then possible to calculate approximate probabilities of finding an inbred that has the favorable allele at {(n/2)+m} loci, where n/2 is the number of favorable alleles in each of the parents and m is the number of additional favorable alleles in the new inbred. See Example 2 below. The number m is assumed to be greater than three because each allele has so small an effect that evaluation techniques are not sensitive enough to detect differences due to three or less favorable alleles. The probabilities in Example 2 are on the order of 10.sup.-5 or smaller and they are the probabilities that at least one genotype with (n/2)+m favorable alleles will exist.

To put this in perspective the number of plants grown on 60 million acres (approximate US corn acreage) at 25000 plants/acre is 1.5.times.10.sup.12.

EXAMPLE 2

Probability of Finding an Inbred With m of n Favorable Alleles

Assume each parent has n/2 of the favorable alleles and only 1/2 of the combinations of loci are economically useful. 

    ______________________________________
    no. of  no. favorable
                       no. additional Probability
    segregating
            alleles in favorable alleles
                                      that genotype
    loci (n)
            Parent (n/2)
                       in new inbred  occurs*
    ______________________________________
    20      10         14             3 .times. 10.sup.-5
    24      12         16             2 .times. 10.sup.-5
    28      14         18             1 .times. 10.sup.-5
    32      16         20             8 .times. 10.sup.-6
    36      18         22             5 .times. 10.sup.-6
    40      20         24             3 .times. 10.sup.-6
    44      22         26             2 .times. 10.sup.-6
    48      24         28             1 .times. 10.sup.-6
    ______________________________________
     *Probability that a useful combination exists, does not include the
     probability of identifying this combination if it does exist.


The possibility of having a usably high probability of being able to identify this genotype based on replicated field testing would be most likely smaller than this, and is a function of how large a population of genotypes is tested and how testing resources are allocated in the testing program.

At Pioneer Hi-Bred International, a typical corn research station has a staff of four, and 20 acres of breeding nursery. Those researchers plant those 20 acres with 25,000 nursery rows, 15,000 yield test plots in 10-15 yield test sites, and one or two disease-screening nurseries. Employing a temporary crew of 20 to 30 pollinators, the station makes about 65,000 hand pollinations per growing season. Thus, one of the largest plant breeding programs in the world does not have a sufficiently large breeding population to be able to rely upon "playing the numbers" to obtain successful research results. Nevertheless, Pioneer's breeders at each station produce from three to ten new inbreds which are proposed for commercial use each year. Over the 32 Pioneer research stations in North America, this amounts to from about 100 to 300 new inbreds proposed for use, and less than 50 and more commonly less than 30 of these inbreds that actually satisfy the performance criteria for commercial use.

This is a result of plant breeders using their skills, experience and intuitive ability to select inbreds having the necessary qualities.

SUMMARY OF THE INVENTION

According to the invention, there is provided a novel inbred corn line, designated PHTD5. This invention thus relates to the seeds of inbred corn line PHTD5, to the plants of inbred corn line PHTD5, and to methods for producing a corn plant produced by crossing the inbred line PHTD5 with itself or another corn line. This invention further relates to hybrid corn seeds and plants produced by crossing the inbred line PHTD5 with another corn line.

Definitions

In the description and examples that follow, a number of terms are used herein. In order to provide a clear and consistent understanding of the specification and claims, including the scope to be given such terms, the following definitions are provided. ABS is in absolute terms and % MN is percent of the mean for the experiments in which the inbred or hybrid was grown.

BAR PLT=BARREN PLANTS. The percent of plants per plot that were not barren (lack ears).

BRT STK=BRITTLE STALKS. This is a measure of the stalk breakage near the time of pollination, and is an indication of whether a hybrid or inbred would snap or break near the time of flowering under severe winds. Data are presented as percentage of plants that did not snap.

BU ACR=YIELD (BUSHELS/ACRE). Actual yield of the grain at harvest in bushels per acre adjusted to 15.5% moisture.

DRP EAR=DROPPED EARS. A measure of the number of dropped ears per plot and represents the percentage of plants that did not drop ears prior to harvest.

EAR HT=EAR HEIGHT. The ear height is a measure from the ground to the highest placed developed ear node attachment and is measured in inches.

EAR SZ=EAR SIZE. A 1 to 9 visual rating of ear size. The higher the rating the larger the ear size.

EST CNT=EARLY STAND COUNT. This is a measure of the stand establishment in the spring and represents the number of plants that emerge on a per plot basis for the inbred or hybrid.

GDU SHD=GDU TO SHED. The number of growing degree units (GDUs) or heat units required for an inbred line or hybrid to have approximately 50 percent of the plants shedding pollen and is measured from the time of planting. Growing degree units are calculated by the Barger Method, where the heat units for a 24-hour period are: ##EQU1##

The highest maximum temperature used is 86.degree. F. and the lowest minimum temperature used is 50.degree. F. For each inbred or hybrid it takes a certain number of GDUs to reach various stages of plant development.

GDU SLK=GDU TO SILK. The number of growing degree units required for an inbred line or hybrid to have approximately 50 percent of the plants with silk emergence from time of planting. Growing degree units are calculated by the Barger Method as given in GDU SHD definition.

GRN APP=GRAIN APPEARANCE. This is a 1 to 9 rating for the general appearance of the shelled grain as it is harvested based on such factors as the color of the harvested grain, any mold on the grain, and any cracked grain. High scores indicate good grain quality.

MST=HARVEST MOISTURE. The moisture is the actual percentage moisture of the grain at harvest.

PLT HT=PLANT HEIGHT. This is a measure of the height of the plant from the ground to the tip of the tassel in inches.

POL SC=POLLEN SCORE. A 1 to 9 visual rating indicating the amount of pollen shed. The higher the score the more pollen shed.

POL WT=POLLEN WEIGHT. This is calculated by dry weight of tassels collected as shedding commences minus dry weight from similar tassels harvested after shedding is complete.

It should be understood that the inbred can, through routine manipulation of cytoplasmic factors, be produced in a cytoplasmic male-sterile form which is otherwise phenotypically identical to the male-fertile form.

PRM=PREDICTED RM. This trait, predicted relative maturity (RM), is based on the harvest moisture of the grain. The relative maturity rating is based on a known set of checks and utilizes standard linear regression analyses and is referred to as the Comparative Relative Maturity Rating System which is similar to the Minnesota Relative Maturity Rating System.

RT LDG=ROOT LODGING. Root lodging is the percentage of plants that do not root lodge; plants that lean from the vertical axis at an approximately 30.degree. angle or greater would be counted as root lodged.

SCT GRN=SCATTER GRAIN. A 1 to 9 visual rating indicating the amount of scatter grain (lack of pollination or kernel abortion) on the ear. The higher the score the less scatter grain.

SDG VGR=SEEDLING VIGOR. This is the visual rating (1 to 9) of the amount of vegetative growth after emergence at the seedling stage (approximately five leaves). A higher score indicates better vigor.

SEL IND=SELECTION INDEX. The selection index gives a single measure of the hybrid's worth based on information for up to five traits. A corn breeder may utilize his or her own set of traits for the selection index. One of the traits that is almost always included is yield. The selection index data presented in the tables represent the mean value averaged across testing stations.

STA GRN=STAY GREEN. Stay green is the measure of plant health near the time of black layer formation (physiological maturity). A high score indicates better late-season plant health.

STK CNT=NUMBER OF PLANTS. This is the final stand or number of plants per plot.

STK LDG=STALK LODGING. This is the percentage of plants that did not stalk lodge (stalk breakage) as measured by either natural lodging or pushing the stalks and determining the percentage of plants that break below the ear.

TAS BLS=TASSEL BLAST. A 1 to 9 visual rating was used to measure the degree of blasting (necrosis due to heat stress) of the tassel at time of flowering. A 1 would indicate a very high level of blasting at time of flowering, while a 9 would have no tassel blasting.

TAS SZ=TASSEL SIZE. A 1 to 9 visual rating was used to indicate the relative size of the tassel. The higher the rating the larger the tassel.

TAS WT=TASSEL WEIGHT. This is the average weight of a tassel (grams) just prior to pollen shed.

TEX EAR=EAR TEXTURE. A 1 to 9 visual rating was used to indicate the relative hardness (smoothness of crown) of mature grain. A 1 would be very soft (extreme dent) while a 9 would be very hard (flinty or very smooth crown).

TILLER=TILLERS. A count of the number of tillers per plot that could possibly shed pollen was taken. Data is given as percentage of tillers: number of tillers per plot divided by number of plants per plot.

TST WT=TEST WEIGHT (UNADJUSTED). The measure of the weight of the grain in pounds for a given volume (bushel).

TST WTA=TEST WEIGHT ADJUSTED. The measure of the weight of the grain in pounds for a given volume (bushel) adjusted for percent moisture.

YLD=YIELD. It is the same as BU ACR ABS.

YLD SC=YIELD SCORE. A 1 to 9 visual rating was used to give a relative rating for yield based on plot ear piles. The higher the rating the greater visual yield appearance.

MDM CPX=Maize Dwarf Mosaic Complex (MDMV=Maize Dwarf Mosaic Virus & MCDV=Maize Chlorotic Dwarf Virus): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

SLF BLT=Southern Leaf Blight (Bipolaris maydis, Helminthosporium maydis): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

NLF BLT=Northern Leaf Blight (Exserohilum turcicum, H. turcicum): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

COM RST=Common Rust (Puccinia sorghi): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

GLF SPT=Gray Leaf Spot (Cercospora zeae-maydis): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

STW WLT=Stewart's Wilt (Erwinia stewartii): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

HD SMT=Head Smut (Sphacelotheca reiliana): Percentage of plants that did not have infection.

EAR MLD=General Ear Mold: Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant. This is based on overall rating for ear mold of mature ears without determining specific mold organism, and may not be predictive for a specific ear mold.

ECB DPE=Dropped ears due to European Corn Borer (Ostrinia nubilalis): Percentage of plants that did not drop ears under second brood corn borer infestation.

ECB 2SC=European Corn Borer Second Brood (Ostrinia nubilalis): Visual rating (1-9 score) of post flowering damage due to infestation by European Corn Borer. A "1" is very susceptible and a "9" is very resistant.

ECB 1LF=European Corn Borer First Brood (Ostrinia nubilalis): Visual rating (1-9 score) of pre-flowering leaf feeding by European Corn Borer. A "1" is very susceptible and a "9" is very resistant.

DETAILED DESCRIPTION OF INVENTION

PHTD5 has good yield over a wide range of environments. It also has good drydown for its maturity.

Inbred corn line PHTD5 is a yellow, dent corn inbred that provides an acceptable male or female parental line in crosses for producing first generation F1 corn hybrids. PHTD5 is widely adapted to the northern latitudes where corn is grown, including Europe. PHTD5 is high yielding with good drydown for its maturity (85 and 90 CRM) and has especially good female seed yields. It is above average for root lodging with reasonable resistance to leaf diseases.

The inbred has shown uniformity and stability within the limits of environmental influence for all the traits as described in the Variety Description Information (Table 1) that follows. Most of the data in the Variety Description information was collected at Johnston, Iowa. The inbred has been self-pollinated and ear-rowed a sufficient number of generations with careful attention paid to uniformity of plant type to ensure homozygosity and phenotypic stability. The line has been increased both by hand and in isolated fields with continued observation for uniformity. No variant traits have been observed or are expected in PHTD5.

Inbred corn line PHTD5, being substantially homozygous, can be reproduced by planting seeds of the line, growing the resulting corn plants under self-pollinating or sib-pollinating conditions with adequate isolation, and harvesting the resulting seed, using techniques familiar to the agricultural arts. 

                  TABLE 1
    ______________________________________
    VARIETY DESCRIPTION INFORMATION
    INBRED = PHTD5
    Type: Dent   Region Best Adapted: North Central
    ______________________________________
    A.  Maturity: Average across maturity zones.
        Heat Unit Shed: 1230
        Heat Unit Silk: 1250
        No. Reps: 23
     ##STR1##
        *If maximum is greater than 86 degrees fahrenheit, then 86
        is used and if minimum is less than 50, then 50 is used.
        Heat units accumulated daily and can not be less than 0.
    B.  Plant Characteristics:
        Plant height (to tassel tip): 184 cm
        Length of top ear internode: 12 cm
        Number of ears per stalk: Slight two ear tendancy
        Ear height (to base of top ear): 92 cm
        Number of tillers: None
        Cytoplasm type: Normal
    C.  Leaf:
        Color: (B14) Dark Green
        Angle from Stalk: 30-60 degrees
        Marginal Waves: (WF9) Few
        Number of Leaves (mature plants): 19
        Sheath Pubescence: (W22) Light
        Longitudinal Creases: (OH56A) Few
        Length (Ear node leaf): 67 cm
        Width (widest point, ear node leaf): 9 cm
    D.  Tassel:
        Number lateral branches: 15
        Branch Angle from central spike: 30-40 degrees
        Pollen Shed: Light based on Pollen Yield Test
        (88% of experiment means)
        Peduncle Length (top leaf to basal branches): 12 cm
        Anther Color: Red
        Glume Color: Green
    E.  Ear (Husked Ear Data Except When Stated Otherwise):
        Length: 13 cm
        Weight: 104 cm
        Mid-point Diameter: 41 mm
        Silk Color: Salmon
        Husk Extension (harvest stage): Medium (barely covering ear)
        Husk Leaf: Short (<8 cm)
        Taper of Ear: Average
        Position of Shank (dry husks): Upright
        Kernel Rows: Straight Indistinct Number = 16
        Husk Color (fresh): Light Green
        Husk Color (dry): Buff
        Shank Length: 13 cm
        Shank (No. of internodes): 8
    F.  Kernel (Dried):
        Size (from ear mid-point)
    Length:   11 mm
    Width:     8 mm
    Thick:     5 mm
        Shape Grade (% rounds): 40-60 (45% medium round based
        on Parent Test Data)
        Pericarp Color: Colorless
        Aleurone Color: Homozygous Yellow
        Endosperm Color: Yellow
        Endosperm Type: Normal Starch
        Gm Wt/100 Seeds (unsized): 28 gm
    G.  Cob:
        Diameter at mid-point: 22 mm
        Strength: Strong
        Color: Red
    H.  Diseases:
        N. Leaf Blight (E. turcicum): Intermediate
        Common Rust (P. sorghi): Resistant
        Stewart's Wilt (E. stewartii): Intermediate
        Common Smut (U. maydis): Highly Resistant
        Head Smut (S. reiliana): Intermediate
        Fusarium Ear Mold (F. monilifirme): Highly Resistant
        Gibberella Ear Rot (G. zeae): Intermediate
    I.  Insects:
        European Corn Borer-1 Leaf Damage (Pre-flowering):
        Susceptible
        European Corn Borer-2 (Post-flowering): Intermediate
        The above descriptions are based on a scale of 1-9, 1 being
        highly susceptible, 9 being highly resistant.
        S (Susceptible): Would generally represent a score of 1-3.
        I (Intermediate): Would generally represent a score of 4-5.
        R (Resistant): Would generally represent a score of 6-7.
        H (Highly Resistant): Would generally represent a score of
        8-9. Highly resistant does not imply the inbred is immune.
    J.  Variety Most Closely Resembling:
    Character  Inbred
    Maturity   PHR25
    Usage      PHR25
    ______________________________________
     PHR25 (PVP Certificate No. 8800002) is a Pioneer HiBred International,
     Inc. proprietary inbred.
     Data for Items B, C, D, E, F, and G is based primarily on a maximum of tw
     reps from Johnson, Iowa grown in 1992, plus description information from
     the maintaining station.


ELECTROPHORESIS RESULTS

Isozyme Genotypes for PHTD5

Isozyme data were generated for inbred corn line PHTD5 according to the procedures described in Stuber, C. W., Wendel, J. F., Goodman, M. M., and Smith, J. S. C., "Techniques and Scoring Procedures for Starch Gel Electrophoresis of Enzymes from Maize (Zea mays L.)", Technical Bulletin No. 286, North Carolina Agricultural Research Service, North Carolina State University, Raleigh, N.C. (1988).

The data in Table 2 compares PHTD5 with its parents, PHH93 and PHR25. 

                  TABLE 2
    ______________________________________
    ELECTROPHORESIS RESULTS FOR PHTD5
    AND ITS PARENTS PHH93 AND PHR25
                     PARENTS
    LOCI    PHTD5          PHH93   PHR25
    ______________________________________
    ACP1    2              2       2
    ADH1    4              4       4
    CAT3    9              9       9
    DIA1    8              8       8
    GOT1    4              4       4
    GOT2    4              4       4
    GOT3    4              4       4
    IDH1    4              4       4
    IDH2    6              6       6
    MDH1    1              1       1
    MDH2    3.5            3.5     3.5
    MDH3    16             16      16
    MDH4    12             12      12
    MDH5    12             12      12
    MMM     4              4       4
    PGM1    9              9       9
    PGM2    4              4       4
    PGD1    3.8            3.8     3.8
    PGD2    5              5       5
    PHI1    4              4       4
    ______________________________________


EXAMPLES

Inbred and Hybrid Performance of PHTD5

In the examples that follow, the traits and characteristics of inbred corn line PHTD5 are given as a line in comparison with other inbreds and in hybrid combination. The data collected on inbred corn line PHTD5 is presented for the key characteristics and traits.

PHTD5 is considered a "direct replacement" for PHR25, however, Table 3A shows PHTD5 has higher yield, grain harvest moisture and test weight compared to PHR25 and thus is markedly superior, as is the performance of its hybrids. (See below) PHTD5 is a shorter inbred with higher ear placement and flowers (GDU Shed and GDU Silk) later than PHR25. PHTD5 has better ear texture and grain appearance than PHR25.

Table 3B compares PHTD5 and PHFR8. PHTD5 has lower yield and test weight than PHFR8. PHTD5 is shorter with higher ear placement and flowers (GDU Shed and GDU Silk) earlier than PHFR8.

Table 3C shows PHTD5 has higher yield and grain harvest moisture but lower test weight than PHM81. PHTD5 is taller with higher ear placement and flowers (GDU Shed and GDU Silk) later than PHM81. PHTD5 has better staygreen than PHM81.

The data in Table 3D shows PHTD5 has lower yield and grain harvest moisture but higher test weight than PHP02. PHTD5 is a shorter inbred and flowers (GDU Shed and GDU Silk) earlier than PHP02.

Table 3E compares PHTD5 to PHG72. PHTD5 has lower yield than PHG72. PHTD5 flowers (GDU Shed and GDU Silk) earlier than PHG72.

Table 4A compares PHTD5 and PHR25 when both were crossed to the same inbred testers. The PHTD5 hybrids have higher yield than the PHR25 hybrids. The PHTD5 hybrids shed (GDU Shed) later than the PHR25 hybrids. The PHTD5 hybrids are slightly taller and have higher ear placement compared to the PHR25 hybrids.

Table 4B compares PHTD5 and PHFR8 when both were crossed to the same inbred testers. The PHTD5 hybrids have higher yield and lower grain harvest moisture than the PHFR8 hybrids. The PHTD5 hybrids shed (GDU Shed) slightly earlier than the PHFR8 hybrids. The PHTD5 hybrids have better seedling vigor and are shorter with lower ear placement compared to the PHFR8 hybrids.

Table 4C compares PHTD5 to PHP02 when both were crossed to the same inbred testers. The PHTD5 hybrids have higher yield, lower grain harvest moisture and higher test weight compared to the PHP02 hybrids. The PHTD5 hybrids shed (GDU Shed) earlier than the PHP02 hybrids. The PHTD5 hybrids have better grain appearance and seedling vigor plus a higher early stand count compared to the PHP02 hybrids. The PHTD5 hybrids are shorter with lower ear placement than the PHP02 hybrids.

Table 5A compares PHTD5 and PHP02 when both were crossed to the same inbred. The PHTD5 hybrid has higher yield, lower grain harvest moisture and higher test weight than the PHP02 hybrid. The PHTD5 hybrid is shorter with lower ear placement and sheds (GDU Shed) earlier than the PHP02 hybrid.

Table 5B compares PHTD5 to PHR25 when both were crossed to the same inbred. The PHTD5 hybrid has higher yield and test weight compared to the PHR25 hybrid. The PHTD5 hybrid has better seedling vigor and higher early stand count than the PHR25 hybrid. The PHTD5 hybrid is taller with higher ear placement and sheds (GDU Shed) later than the PHR25 hybrid.

Table 5C compares PHTD5 to PHR25 when both were crossed to the same inbred, an inbred different than in Table 5B. The PHTD5 hybrid is higher yielding than the PHR25 hybrid. The PHTD5 hybrid has better staygreen and better seedling vigor compared to the PHR25 hybrid. The hybrids have similar plant height but the PHTD5 hybrid has higher ear placement and sheds (GDU Shed) later than the PHR25 hybrid.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 compares the yield of PHTD5 and PHR25. PHTD5 and PHR25 have similar yield in low yield environments but PHTD5 has better yield in high yield environments.

FIG. 2 compares the yield of PHTD5 and PHFR8. PHTD5 and PHFR8 have similar yield in low yield environments. Both inbreds have above average yield but PHFR8 has higher yield in high yield environments compared to PHTD5.

FIG. 3 compares the yield of PHTD5 and PHM81. PHTD5 has above average yield whereas PHM81 has below average yield across all environments. PHTD5 has higher yield than PHM81 across all environments with the greatest differential in low yield environments.

FIG. 4 compares the yield of PHTD5 and PHP02. Both inbreds have above average yield but PHP02 is higher yielding across all environments than PHTD5. 

                                      TABLE 3A
    __________________________________________________________________________
    PAIRED INBRED COMPARISON DATA
    VARIETY #1-PHTD5
    VARIETY #2-PHR25
                BU  BU  YLD      EAR BAR PLT EAR  SDG EST DRP TIL
            VAR ACR ACR SC   MST SZ  PLT HT  HT   VGR CNT EAR LER
    DEPT    #   ABS %MN ABS  ABS ABS ABS ABS ABS  ABS ABS ABS ABS
    __________________________________________________________________________
    TOTAL SUM
            1   70.0
                    111 6.1  18.6
                                 5.0 98.8
                                         69.0
                                             28.1 5.8 39.7
                                                          99.7
                                                              1.5
            2   63.5
                    101 5.7  18.2
                                 4.8 98.0
                                         73.0
                                             26.3 4.8 38.8
                                                          99.8
                                                              1.6
            LOCS
                12  12  9    12  5   11  22  22   18  36  6   26
            REPS
                38  38  9    38  5   19  37  36   29  83  14  44
            DIFF
                6.5 10  0.4  0.4 0.2 0.8 4.0 1.8  1.0 0.9 0.2 0.1
            PROB
                .051*
                    0.79*
                        .272 .161
                                 .704
                                     .403
                                         .000#
                                             .060*
                                                  .025+
                                                      .347
                                                          .363
                                                              .933
    __________________________________________________________________________
                GDU GDU POL POL  POL TAS TAS TEX  TST GRN SCT STA
            VAR SHD SLK WT  WT   SC  BLS SZ  EAR  WT  APP GRN GRN
    DEPT    #   ABS ABS ABS %MN  ABS ABS ABS ABS  ABS ABS ABS ABS
    __________________________________________________________________________
    TOTAL SUM
            1   1205
                    1213
                        106.3
                            87   5.4 8.4 5.5 3.5  58.6
                                                      5.7 8.2 3.0
            2   1171
                    1187
                        123.9
                            102  5.5 8.9 5.6 2.5  56.3
                                                      3.7 7.9 1.9
            LOCS
                31  26  6   6    16  4   12  6    12  6   9   5
            REPS
                44  33  12  12   23  7   12  6    38  13  9   11
            DIFF
                34  26  17.7
                            15   0.1 0.5 0.1 1.0  2.3 2.0 0.3 1.1
            PROB
                .000#
                    .005#
                        .266
                            .286 .844
                                     .391
                                         .862
                                             .041+
                                                  .000#
                                                      .048+
                                                          .397
                                                              .256
    __________________________________________________________________________
                                          STK RT  EAR STW ECB ECB
                                      VAR LDG LDG MLD WLT 1LF 2SC
                              DEPT    #   ABS ABS ABS ABS ABS ABS
    __________________________________________________________________________
                              TOTAL SUM
                                      1   95.3
                                              95.2
                                                  7.4 5.0 3.3 4.8
                                      2   95.6
                                              84.9
                                                  7.3 4.0 4.5 4.3
                                      LOCS
                                          9   4   7   1   4   2
                                      REPS
                                          27  10  7   1   4   3
                                      DIFF
                                          0.3 10.3
                                                  0.1 1.0 1.3 0.5
                                      PROB
                                          .912
                                              .187
                                                  .853    .194
                                                              .500
    __________________________________________________________________________
     * = 10% SIG
     + = 5% SIG
     # = 1% SIG


                                  TABLE 3B
    __________________________________________________________________________
    PAIRED INBRED COMPARISON DATA
    VARIETY #1-PHTD5
    VARIETY #2-PHFR8
                BU  BU  YLD      EAR BAR PLT EAR  SDG EST DRP TIL
            VAR ACR ACR SC  MST  SZ  PLT HT  HT   VGR CNT EAR LER
    DEPT    #   ABS %MN ABS ABS  ABS ABS ABS ABS  ABS ABS ABS ABS
    __________________________________________________________________________
    TOTAL SUM
            1   81.2
                    116 6.0 18.8 5.0 97.3
                                         69.7
                                             28.8 5.5 44.7
                                                          99.7
                                                              1.3
            2   92.4
                    131 6.2 20.3 5.4 98.6
                                         71.1
                                             27.5 5.2 46.1
                                                          99.9
                                                              2.6
            LOCS
                30  30  9   36   5   26  33  33   29  64  18  32
            REPS
                62  62  9   68   5   31  51  51   39  120 38  50
            DIFF
                11.3
                    15  0.2 1.4  0.4 1.3 1.4 1.3  0.3 1.4 0.2 1.3
            PROB
                .001#
                    .001#
                        .665
                            .000#
                                 .477
                                     .218
                                         .019+
                                             .054*
                                                  .279
                                                      .039+
                                                          .286
                                                              .125
    __________________________________________________________________________
                GDU GDU POL POL  POL TAS TAS TEX  TST GRN SCT STA
            VAR SHD SLK WT  WT   SC  BLS SZ  EAR  WT  APP GRN GRN
    DEPT    #   ABS ABS ABS %MN  ABS ABS ABS ABS  ABS ABS ABS ABS
    __________________________________________________________________________
    TOTAL SUM
            1   1212
                    1218
                        112.7
                            88   5.6 8.4 5.5 3.6  56.7
                                                      5.5 8.0 4.6
            2   1229
                    1228
                        113.3
                            91   5.9 8.9 5.6 4.4  56.7
                                                      6.0 8.3 5.9
            LOCS
                43  33  9   9    20  5   14  7    30  18  9   13
            REPS
                62  43  18  18   30  9   14  7    62  37  9   23
            DIFF
                17  10  0.5 3    0.3 0.5 0.1 0.9  0.1 0.4 0.3 1.3
            PROB
                .000#
                    .031+
                        .962
                            .751 .239
                                     .266
                                         .635
                                             .045+
                                                  .684
                                                      .013+
                                                          .081*
                                                              .000#
    __________________________________________________________________________
                                       STK RT  EAR NLF STW ECB ECB
                                   VAR LDG LDG MLD BLT WLT 1LF 2SC
                           DEPT    #   ABS ABS ABS ABS ABS ABS ABS
    __________________________________________________________________________
                           TOTAL SUM
                                   1   95.3
                                           97.1
                                               7.0 3.5 5.0 3.4 5.0
                                   2   97.0
                                           89.6
                                               6.7 2.5 6.0 5.9 5.5
                                   LOCS
                                       21  7   7   2   1   8   6
                                   REPS
                                       44  16  7   2   1   10  10
                                   DIFF
                                       0.3 1.0 1.0 2.5 0.5 2.5 0.5
                                   PROB
                                       .090*
                                           .101
                                               .715
                                                   .500    .001#
                                                               .229
    __________________________________________________________________________
     * = 10% SIG
     + = 5% SIG
     # = 1% SIG


                                  TABLE 3C
    __________________________________________________________________________
    PAIRED INBRED COMPARISON DATA
    VARIETY #1-PHTD5
    VARIETY #2-PHM81
                BU  BU  YLD      EAR BAR PLT EAR  SDG EST DRP TIL
            VAR ACR ACR SC  MST  SZ  PLT HT  HT   VGR CNT EAR LER
    DEPT    #   ABS %MN ABS ABS  ABS ABS ABS ABS  ABS ABS ABS ABS
    __________________________________________________________________________
    TOTAL SUM
            1   81.5
                    116 6.3 19.1 5.0 97.4
                                         69.7
                                             29.1 5.9 45.7
                                                          99.7
                                                              1.4
            2   64.1
                    90  6.6 18.0 5.8 95.8
                                         55.6
                                             19.9 4.5 43.8
                                                          99.9
                                                              1.9
            LOCS
                27  27  10  33   5   21  31  31   22  43  17  19
            REPS
                56  56  10  62   5   23  47  47   29  65  36  25
            DIFF
                17.3
                    26  0.3 1.0  0.8 1.7 14.1
                                             9.2  1.3 1.9 0.3 0.5
            PROB
                .000#
                    .000#
                        .279
                            .000#
                                 .099*
                                     .169
                                         .000#
                                             .000#
                                                  .000#
                                                      .019+
                                                          .167
                                                              .453
    __________________________________________________________________________
                GDU GDU POL TAS  TAS TEX TST GRN  SCT STA STK RT
            VAR SHD SLK WT  BLS  SZ  EAR WT  APP  GRN GRN LDG LDG
    DEPT    #   ABS ABS %MN ABS  ABS ABS ABS ABS  ABS ABS ABS ABS
    __________________________________________________________________________
    TOTAL SUM
            1   1209
                    1206
                        5.9 9.0  5.8 3.6 56.4
                                             5.5  8.1 6.1 95.5
                                                              97.1
            2   1119
                    1121
                        6.6 9.0  5.2 5.1 58.5
                                             5.8  8.5 4.8 94.4
                                                              98.5
            LOCS
                29  20  10  1    13  7   27  18   10  7   17  7
            REPS
                37  20  10  1    13  7   56  37   10  14  36  16
            DIFF
                90  85  0.7 0.0  0.6 1.6 2.1 0.3  0.4 1.4 1.1 1.4
            PROB
                .000#
                    .000#
                        .257     .193
                                     .005#
                                         .000#
                                             .362 .309
                                                      .018+
                                                          .379
                                                              .184
    __________________________________________________________________________
                                                   EAR STW ECB ECB
                                               VAR MLD WLT 1LF 2SC
                                       DEPT    #   ABS ABS ABS ABS
    __________________________________________________________________________
                                       TOTAL SUM
                                               1   7.3 5.0 3.3 5.0
                                               2   7.5 2.0 3.0 5.0
                                               LOCS
                                                   8   1   4   5
                                               REPS
                                                   8   1   4   9
                                               DIFF
                                                   0.3 3.0 0.3 0.0
                                               PROB
                                                   .790    .638
                                                               .000#
    __________________________________________________________________________
     * = 10% SIG
     + = 5% SIG
     # = 1% SIG


                                  TABLE 3D
    __________________________________________________________________________
    PAIRED INBRED COMPARISONS DATA
    VARIETY #1-PHTD5
    VARIETY #2-PHP02
                BU  BU  YLD      EAR BAR PLT EAR  SDG EST DRP TIL
            VAR ACR ACR SC  MST  SZ  PLT HT  HT   VGR CNT EAR LER
    DEPT    #   ABS %MN ABS ABS  ABS ABS ABS ABS  ABS ABS ABS ABS
    __________________________________________________________________________
    TOTAL SUM
            1   84.0
                    118 6.2 19.1 5.0 98.1
                                         69.2
                                             28.7 5.5 41.6
                                                          99.7
                                                              1.2
            2   101.4
                    143 7.6 23.2 7.6 99.6
                                         74.7
                                             28.9 4.4 39.0
                                                          99.7
                                                              0.8
            LOCS
                21  21  9   27   5   17  29  29   28  46  14  19
            REPS
                42  42  9   50   5   20  43  43   37  86  28  23
            DIFF
                17.4
                    25  1.3 4.0  2.6 1.6 5.5 0.2  1.1 2.6 0.0 0.4
            PROB
                .000#
                    .000#
                        .016+
                            .000#
                                 .025+
                                     .077*
                                         .000#
                                             .814 .000#
                                                      .000#
                                                          .919
                                                              .653
    __________________________________________________________________________
                GDU GDU POL TAS  TAS TEX TST GRN  SCT STA STK RT
            VAR SHD SLK SC  BLS  SZ  EAR WT  APP  GRN GRN LDG LDG
    DEPT    #   ABS ABS ABS ABS  ABS ABS ABS ABS  ABS ABS ABS ABS
    __________________________________________________________________________
    TOTAL SUM
            1   1206
                    1209
                        5.8 9.0  5.4 3.3 56.5
                                             5.3  8.2 4.6 95.8
                                                              97.1
            2   1250
                    1276
                        5.6 9.0  6.2 3.2 53.7
                                             5.4  8.3 6.0 96.1
                                                              94.1
            LOCS
                30  22  9   1    13  6   21  13   9   13  17  5
            REPS
                37  22  9   1    13  6   42  25   9   23  34  10
            DIFF
                44  67  0.2 0.0  0.8 0.2 0.8 0.0  0.1 1.4 0.3 3.0
            PROB
                .000#
                    .000#
                        .729     .065*
                                     .793
                                         .000#
                                             .928 .760
                                                      .002#
                                                          .803
                                                              .410
    __________________________________________________________________________
                                               EAR NLF STW ECB ECB
                                           VAR MLD BLT WLT 1LF 2SC
                                   DEPT    #   ABS ABS ABS ABS ABS
    __________________________________________________________________________
                                   TOTAL SUM
                                           1   7.6 3.5 5.0 3.5 5.0
                                           2   8.0 4.0 5.0 6.3 5.6
                                           LOCS
                                               7   2   1   6   6
                                           REPS
                                               7   2   1   6   10
                                           DIFF
                                               0.4 0.5 0.0 2.8 0.6
                                           PROB
                                               .658
                                                   .500    .038+
                                                               .374
    __________________________________________________________________________
     * = 10% SIG
     + =  5% SIG
     # = 1% SIG


                                  TABLE 3E
    __________________________________________________________________________
    PAIRED INBRED COMPARISON DATA
    VARIETY #1-PHTD5
    VARIETY #2-PHG72
                BU  BU  YLD      EAR BAR PLT EAR  SDG EST TIL GDU
            VAR ACR ACR SC  MST  SZ  PLT HT  HT   VGR CNT LER SHD
    DEPT    #   ABS %MN ABS ABS  ABS ABS ABS ABS  ABS ABS ABS ABS
    __________________________________________________________________________
    TOTAL SUM
            1   78.5
                    113 5.8 16.5 5.0 99.2
                                         72.5
                                             29.8 5.6 40.2
                                                          1.8 1209
            2   97.4
                    141 6.7 16.8 5.5 99.1
                                         73.2
                                             29.2 5.4 42.3
                                                          5.6 1256
            LOCS
                3   3   6   3    4   7   13  13   17  30  21  27
            REPS
                6   6   6   6    4   10  15  15   20  42  32  37
            DIFF
                18.9
                    28  0.8 0.3  0.5 0.1 0.7 0.7  0.2 2.1 3.9 45
            PROB
                .020+
                    .034+
                        .259
                            .576 .604
                                     .951
                                         .634
                                             .571 .590
                                                      .059*
                                                          .018+
                                                              .000#
    __________________________________________________________________________
                GDU POL POL POL  TAS TAS TEX TST  GRN SCT STA STK
            VAR SLK WT  WT  SC   BLS SZ  EAR WT   APP GRN GRN LDG
    DEPT    #   ABS ABS %MN ABS  ABS ABS ABS ABS  ABS ABS ABS ABS
    __________________________________________________________________________
    TOTAL SUM
            1   1224
                    116.8
                        90  5.1  8.4 5.9 3.6 59.0 4.0 8.2 3.1 96.9
            2   1296
                    155.3
                        126 6.2  9.0 6.1 5.4 60.2 7.0 8.8 3.0 97.7
            LOCS
                25  8   8   15   5   9   5   3    1   6   4   3
            REPS
                34  16  16  24   9   9   5   6    1   6   7   6
            DIFF
                72  38.5
                        35  1.1  0.6 0.2 1.8 1.2  3.0 0.7 0.1 0.8
            PROB
                .000#
                    .045+
                        .059*
                            .012+
                                 .284
                                     .512
                                         .037+
                                             .184     .175
                                                          .913
                                                              .403
    __________________________________________________________________________
                                               EAR NLF STM ECB ECB
                                           VAR MLD BLT WLT 1LF 2SC
                                   DEPT    #   ABS ABS ABS ABS ABS
    __________________________________________________________________________
                                   TOTAL SUM
                                           1   7.6 4.0 5.0 3.0 5.0
                                           2   8.2 5.0 6.0 5.5 4.0
                                           LOCS
                                               5   1   1   4   1
                                           REPS
                                               5   1   1   4   1
                                           DIFF
                                               0.6 1.0 1.0 2.5 1.0
                                           PROB
                                               .591        .063*
    __________________________________________________________________________
     * = 10% SIG
     + = 5% SIG
     #  = 1% SIG


                                  TABLE 4A
    __________________________________________________________________________
    AVERAGE INBRED BY TESTER PERFORMANCE COMPARING PHR25 TO PHTD5
    CROSSED TO THE SAME INBRED TESTERS AND GROWN IN THE SAME
    EXPERIMENTS. ALL VALUES ARE EXPRESSED AS PERCENT OF THE
    EXPERIMENT MEAN EXCEPT PREDICTED RM, SELECTION INDEX, AND
    YIELD (BU/ACR), WHICH ARE GIVEN IN ABSOLUTE UNITS.
                     SEL
                        BU       GDU PRM STK RT
           INBRED
                 PRM IND
                        ACR
                           YLD
                              MST
                                 SHD SHD LDG LDG
    __________________________________________________________________________
    TOTAL  REPLIC.
                 44  43 44 44 44 48  13  55  4
    MEAN WTS
           PHR25 87  108
                        114
                           106
                              90 99  86  102 91
    MEAN WTS
           PHTD5 88  111
                        117
                           109
                              90 102 91  96  101
           DIFF.     2  3  4  0  3   4   5   11
    __________________________________________________________________________
                    TST GRN SDG EST
                                   STK
                                      PLT
                                         EAR DRP
              INBRED
                    WTA APP VGR CNT
                                   CNT
                                      HT HT  EAR
    __________________________________________________________________________
    TOTAL     REPLIC.
                    44  37  55  92 112
                                      52 52  32
    MEAN WTS  PHR25 99  97  93  97 100
                                      97 97  100
    MEAN WTS  PHTD5 99  99  110 103
                                   100
                                      99 106 100
              DIFF. 1   2   17  5  0  2  9   0
    __________________________________________________________________________


                                  TABLE 4B
    __________________________________________________________________________
    AVERAGE INBRED BY TESTER PERFORMANCE COMPARING PHFR8 TO PHTD5
    CROSSED TO THE SAME INBRED TESTERS AND GROWN IN THE SAME
    EXPERIMENTS. ALL VALUES ARE EXPRESSED AS PERCENT OF THE
    EXPERIMENT MEAN EXCEPT PREDICTED RM, SELECTION INDEX, AND
    YIELD (BU/ACR).
                     SEL
                        BU       GDU PRM STK RT  STA
           INBRED
                 PRM IND
                        ACR
                           YLD
                              MST
                                 SHD SHD LDG LDG GRN
    __________________________________________________________________________
    TOTAL  REPLIC.
                 41  41 41 41 41 14  6   34  7   1
    MEAN WTS
           PHFR8 96  105
                        128
                           103
                              105
                                 101 96  102 103 118
    MEAN WTS
           PHTD5 92  109
                        131
                           107
                              94 99  92  97  104 67
           DIFF. 3   4  3  4  11 1   4   5   1   50
    __________________________________________________________________________
                     TST GRN SDG EST
                                    STK
                                       PLT
                                          EAR DRP BRT
               INBRED
                     WTA APP VGR CNT
                                    CNT
                                       HT HT  EAR STK
    __________________________________________________________________________
    TOTAL      REPLIC.
                     39  21  22  54 69 30 30  17  1
    MEAN WTS   PHFR8 99  99  92  101
                                    101
                                       102
                                          103 100 100
    MEAN WTS   PHTD5 98  99  112 101
                                    100
                                       100
                                          102 100 100
               DIFF. 1   1   19  0  0  2  1   0
    __________________________________________________________________________


                                  TABLE 4C
    __________________________________________________________________________
    AVERAGE INBRED BY TESTER PERFORMANCE COMPARING PHP02 TO PHTD5
    CROSSED TO THE SAME INBRED TESTERS AND GROWN IN THE SAME
    EXPERIMENTS. ALL VALUES ARE EXPRESSED AS PERCENT OF THE
    EXPERIMENT MEAN EXCEPT PREDICTED RM, SELECTION INDEX, AND
    YIELD (BU/ACR).
                     SEL
                        BU       GDU PRM STK TST
           INBRED
                 PRM IND
                        ACR
                           YLD
                              MSY
                                 SHD SHD LDG WTA
    __________________________________________________________________________
    TOTAL  REPLIC.
                 19  18 19 19 19 9   5   17  19
    MEAN WTS
           PHP02 96  103
                        115
                           103
                              111
                                 102 95  99  97
    MEAN WTS
           PHTD5 87  111
                        119
                           108
                              84 98  91  100 99
           DIFF. 9   8  4  5  27 4   4   1   2
    __________________________________________________________________________
                        GRN SDG EST
                                   STK
                                      PLT
                                         EAR DRP
                  INBRED
                        APP VGR CNT
                                   CNT
                                      HT HT  EAR
    __________________________________________________________________________
           TOTAL  REPLIC.
                        14  14  18 23 14 14  8
           MEAN WTS
                  PHP02 97  107 102
                                   100
                                      103
                                         110 100
           MEAN WTS
                  PHTD5 101 109 104
                                   100
                                      96 101 100
                  DIFF. 4   2   2  1  7  9   0
    __________________________________________________________________________


                                  TABLE 5A
    __________________________________________________________________________
    VARIETY #1-PHTD5 HYBRID
    VARIETY #2-PHP02 HYBRID
                    PRM BU  BU      STK TST GRN
            VAR     PRM ACR ACR MST LDG WTA APP
    DEPT    #   PRM SHD ABS %MN %MN %MN %MN %MN
    __________________________________________________________________________
    TOTAL SUM
            1   88  91  122.3
                            107 83  101 99  100
            2   96  95  117.7
                            102 111 98  97  98
            LOCS
                6   5   14  14  14  13  14  12
            REPS
                6   5   17  17  17  15  17  14
            DIFF
                9   4   4.6 5   28  2   2   1
            PROB
                .000#
                    .020+
                        .223
                            .254
                                .000#
                                    .477
                                        .015+
                                            .871
    __________________________________________________________________________
                    SDG EST STK PLT EAR DRP GDU
                VAR VGR CNT CNT HT  HT  EAR SHD
    DEPT        #   %MN %MN %MN %MN %MN %MN %MN
    __________________________________________________________________________
    TOTAL SUM   1   107 104 101 96  101 100 98
                2   105 102 100 103 111 100 101
                LOCS
                    11  9   19  12  12  7   6
                REPS
                    14  13  23  14  14  8   9
                DIFF
                    2   2   1   7   10  0   3
                PROB
                    .757
                        .402
                            .226
                                .000#
                                    .031+
                                        .356
                                            .008#
    __________________________________________________________________________
     * = 10% SIG
     + = 5% SIG
     # = 1% SIG


                                  TABLE 5B
    __________________________________________________________________________
    VARIETY #1-PHTD5 HYBRID
    VARIETY #2-PHR25 HYBRID
                    PRM BU  BU      STK RT  TST
            VAR     PRM ACR ACR MST LDG LDG WTA
    DEPT    #   PRM SHD ABS %MN %MN %MN %MN %MN
    __________________________________________________________________________
    TOTAL SUM
            1   87  91  115.6
                            106 89  101 103 99
            2   87  87  112.8
                            103 89  103 100 98
            LOCS
                10  10  30  30  30  29  1   25
            REPS
                10  10  42  42  42  44  2   33
            DIFF
                0   5   2.8 3   1   2   3   1
            PROB
                .753
                    .000#
                        .236
                            .256
                                .628
                                    .192    0.13+
    __________________________________________________________________________
                GRN SDG EST STK PLT EAR DRP GDU
            VAR APP VGR CNT CNT HT  HT  EAR SHD
    DEPT    #   %MN %MN %MN %MN %MN %MN %MN %MN
    __________________________________________________________________________
    TOTAL SUM
            1   100 106 103 101 98  105 100 101
            2   97  87  93  100 95  96  100 98
            LOCS
                21  21  16  40  20  20  12  14
            REPS
                32  30  26  61  31  31  18  27
            DIFF
                4   19  10  0   3   9   0   4
            PROB
                .318
                    .000#
                        .000#
                            .273
                                .000#
                                    .000#
                                        .190
                                            .000#
    __________________________________________________________________________
     * = 10% SIG
     + = 5% SIG
     # = 1% SIG


                                  TABLE 5C
    __________________________________________________________________________
    VARIETY #1-PHTD5 HYBRID
    VARIETY #2-PHR25 HYBRID
                    PRM BU  BU      STK RT  STA TST
            VAR     PRM ACR ACR MST LDG LDG GRN WTA
    DEPT    #   PRM SHD ABS %MN %MN %MN %MN %MN %MN
    __________________________________________________________________________
    TOTAL SUM
            1   88  90  122.5
                            114 94  93  103 112 100
            2   88  86  116.0
                            108 93  100 91  83  99
            LOCS
                6   7   27  27  27  28  2   3   23
            REPS
                6   7   39  39  39  44  4   7   34
            DIFF
                0   4   6.5 6   1   7   12  29  0
            PROB
                .695
                    .000#
                        .018+
                            .032+
                                .502
                                    .002#
                                        .332
                                            .038+
                                                .350
    __________________________________________________________________________
                GRN SDG EST STK PLT EAR DRP BRT GDU
            VAR APP VGR CNT CNT HT  HT  EAR STK SHD
    DEPT    #   %MN %MN %MN %MN %MN %MN %MN %MN %MN
    __________________________________________________________________________
    TOTAL SUM
            1   96  115 103 100 98  105 100 101 101
            2   91  100 101 100 97  94  100 101 98
            LOCS
                20  21  16  35  18  18  13  1   11
            REPS
                32  34  28  55  28  28  24  2   20
            PROB
                .251
                    .003#
                        .150
                            .747
                                .314
                                    .000#
                                        .187    .000#
    __________________________________________________________________________
     * = 10% SIG
     + = 5% SIG
     # = 1% SIG


Industrial Applicability

The foregoing is set forth by way of example and is not intended to limit the scope of the invention.

This invention also is directed to methods for producing a corn plant by crossing a first parent corn plant with a second parent corn plant wherein the first or second parent corn plant is an inbred corn plant from the line PHTD5. Further, both first and second parent corn plants can come from the inbred corn line PHTD5. Thus, any such methods using the inbred corn line PHTD5 are part of this invention: selfing, backcrosses, hybrid production, crosses to populations, and the like. It also would include more unconventional methods of combining the inbred with another such as using various culturing techniques known to those skilled in the art. All plants produced using inbred corn line PHTD5 as a parent are within the scope of this invention. Advantageously, the inbred corn line is used in crosses with other, different, corn inbreds to produce first generation (F.sub.1) corn hybrid seeds and plants with superior characteristics.

Corn plants (Zea mays L.) can be bred by both self-pollination and cross-pollination techniques. Corn has male flowers, located on the tassel, and female flowers, located on the ear, on the same plant. Natural pollination occurs in corn when wind blows pollen from the tassels to the silks that protrude from the tops of the incipient ears. Backcrossing can be used to transfer monogenic traits from one line to another. This can be accomplished for example by first crossing a superior inbred (A) (recurrent parent) to a donor inbred (non-recurrent parent), which carries the appropriate gene(s) for the trait in question. The progeny of this cross is then mated back to the superior recurrent parent (A) followed by selection in the resultant progeny for the desired trait to be transferred from the non-recurrent parent. After five or more backcross generations with selection for the desired trait, the progeny will be heterozygous for loci controlling the characteristic being transferred, but will be like the superior parent for most or almost all other genes. The last backcross generation would be selfed to give pure breeding progeny for the gene(s) being transferred.

Hybrid corn seed is produced by planting male and female parental lines in sufficient proximity to permit pollination of the female line by the male line ("pollinating proximity"). To assure genetic uniformity and avoid self-pollination, steps are taken to prevent pollen formation by the plants of the parental line chosen to serve as the female. This is most commonly done by manual detasseling. Alternate strips of the parental lines of corn are planted in a field, and the pollen-bearing tassels are physically removed from the female plants, either by hand or by machine. Providing that there is sufficient isolation from other sources of corn pollen, the ears of the female plants will be fertilized only by pollen from the male plants, and the resulting seed is therefore hybrid and will form hybrid plants. In a single-cross hybrid, both parents are inbred lines. In a double-cross hybrid, both parents are the F.sub.1 offspring of a cross of two inbred lines. In a three-way cross, one of the parents is an inbred line and the other parent is an F.sub.1 hybrid. Each cross is made in the manner described herein.

Unfortunately, the manual detasseling process is not entirely reliable. Occasionally a female plant will be blown over by a storm and escape detasseling. Or, a detasseler will not completely remove the tassel of the plant. In either event, the female plant will successfully shed pollen and some female plants will be self-pollinated. This will result in seed of the female inbred being harvested along with the hybrid seed which is normally produced.

Alternatively, the female inbred can be mechanically detasseled. Mechanical detasseling is approximately as reliable as manual detasseling, but is faster and less costly. However, most detasseling machines produce more damage to the plants than manual detasseling.

The laborious detasseling process can be avoided by using cytoplasmic male-sterile (CMS) inbreds. Plants of a CMS inbred are male sterile (do not form pollen) as a result of cytoplasmic factors resulting from the cytoplasmic, as distinguished from the nuclear, genome. Thus, this characteristic is inherited exclusively through the female parent, since the female parent provides the cytoplasm of the fertilized seed. CMS plants are fertilized with pollen from another inbred that is not male-sterile. Pollen from the male parent may or may not contribute genes that make the hybrid plants male-fertile. Usually seed from detasseled normal maize and CMS-produced seed of the same hybrid must be blended to insure that adequate pollen loads are available for fertilization when the hybrid plants are grown.

There can be other drawbacks to CMS. One is an historically observed association of a specific variant of CMS with susceptibility to certain crop diseases. This problem has led to widespread abandonment of use of that CMS variant in producing hybrid maize. In addition, CMS sometimes has a negative association with agronomic performance, particularly in the areas of stalk quality, early seedling vigor, and yield. Finally, CMS sometimes exhibits the potential for breakdown of sterility in certain environments, rendering CMS lines unreliable for hybrid seed production.

Another form of sterility, genic male sterility, is disclosed in U.S. Pat. Nos. 4,654,465 and 4,727,219 to Brar et al. However, this form of genetic male sterility requires maintenance of multiple mutant genes at separate locations within the genome and requires a complex marker system to track the genes and make use of the system convenient.

Another form of male sterility is imparted in a manner by which expression of a transgene produces a "pollen-toxic" compound which blocks pollen formation in some manner.

Still another form of genetic male sterility uses an inducible promoter to regulate expression of a gene which is known to be critical in microsporogenesis, i.e., the production of pollen. The selected gene is cloned, its native promoter removed, and the modified gene is inserted into an expression sequence with an inducible promoter responsive to external control. Preferably, the promoter is one which responds to application of a specific non-phytotoxic chemical to the plant.

Using transformation and gene substitution, the "critical" gene is deleted from the genome of the plant and replaced by the genetically-engineered gene incorporated into the expression sequence with the inducible promoter. In this method, the inducible promoter is used to induce fertility, not sterility. The selected gene's promoter sequences are removed so that the gene is not transcribed and the plant is male sterile. When it is desired to increase the male-sterile plant, male fertility is restored by inducing expression of the critical gene with a specific non-phytotoxic chemical. Any of the foregoing methods and combinations thereof can be used to prevent pollen formation by the female parent of the hybrid.

As used herein, the term plant includes plant cells, plant protoplasts, plant cell tissue cultures from which corn plants can be regenerated, plant calli, plant clumps, and plant cells that are intact in plants or parts of plants, such as embryos, pollen, flowers, kernels, ears, cobs, leaves, husks, stalks, roots, root tips, anthers, silks, and the like.

Duncan, Williams, Zehr, and Widholm, Planta, (1985) 165:322-332 reflects that 97% of the plants cultured which produced callus were capable of plant regeneration. Subsequent experiments with both inbreds and hybrids produced 91% regenerable callus which produced plants. In a further study in 1988, Songstad, Duncan & Widholm in Plant Cell Reports (1988), 7:262-265 reports several media additions which enhance regenerability of callus of two inbred lines. Other published reports also indicated that "nontraditional" tissues are capable of producing somatic embryogenesis and plant regeneration. K. P. Rao, et al., Maize Genetics Cooperation Newsletter, 60:64-65 (1986), refers to somatic embryogenesis from glume callus cultures and B. V. Conger, et al., Plant Cell Reports, 6:345-347 (1987) indicates somatic embryogenesis from the tissue cultures of maize leaf segments. Thus, it is clear from the literature that the state of the art is such that these methods of obtaining plants are, and were, "conventional" in the sense that they are routinely used and have a very high rate of success.

Tissue culture of corn is described in European Patent Application, publication 160,390, incorporated herein by reference. Corn tissue culture procedures are also described in Green and Rhodes, "Plant Regeneration in Tissue Culture of Maize," Maize for Biological Research (Plant Molecular Biology Association, Charlottesville, Va. 1982, at 367-372) and in Duncan, et al., "The Production of Callus Capable of Plant Regeneration from Immature Embryos of Numerous Zea Mays Genotypes," 165 Planta 322-332 (1985). Thus, another aspect of this invention is to provide cells which upon growth and differentiation produce corn plants having the physiological and morphological characteristics of the inbred line PHTD5.

Corn is used as human food, livestock feed, and as raw material in industry. The food uses of corn, in addition to human consumption of corn kernels, include both products of dry- and wet-milling industries. The principal products of corn dry milling are grits, meal and flour. The corn wet-milling industry can provide corn starch, corn syrups, and dextrose for food use. Corn oil is recovered from corn germ, which is a by-product of both dry- and wet-milling industries.

Corn, including both grain and non-grain portions of the plant, is also used extensively as livestock feed, primarily for beef cattle, dairy cattle, hogs, and poultry.

Industrial uses of corn are mainly from corn starch in the wet-milling industry and corn flour in the dry-milling industry. The industrial applications of corn starch and flour are based on functional properties, such as viscosity, film formation, adhesive properties, and ability to suspend particles. The corn starch and flour have application in the paper and textile industries. Other industrial uses include applications in adhesives, building materials, foundry binders, laundry starches, explosives, oil-well muds, and other mining applications.

Plant parts other than the grain of corn are also used in industry. Stalks and husks are made into paper and wallboard and cobs are used for fuel and to make charcoal.

The seed of inbred corn line PHTD5, the plant produced from the inbred seed, the hybrid corn plant produced from the crossing of the inbred, hybrid seed, and various parts of the hybrid corn plant can be utilized for human food, livestock feed, and as a raw material in industry.

Although the foregoing invention has been described in some detail by way of illustration and example for the purposes of clarity and understanding, it will be obvious that certain changes and modifications may be practiced within the scope of the invention, as limited only by the scope of the appended claims.

Deposits

Applicant has made a deposit of at least 2500 seeds of Inbred Corn Line PHTD5 with the American Type Culture Collection (ATCC), Rockville, Md. 20852 USA, ATCC Accession No. 97373. The seeds deposited with the ATCC on Dec. 8, 1995 were taken from the deposit maintained by Pioneer Hi-Bred International, Inc., 700 Capital Square, 400 Locust Street, Des Moines, Iowa 50309-2340 since prior to the filing date of this application. This deposit of the Inbred Corn Line PHTD5 will be maintained in the ATCC depository, which is a public depository, for a period of 30 years, or 5 years after the most recent request, or for the effective life of the patent, whichever is longer, and will be replaced if it becomes nonviable during that period. Additionally, Applicant has satisfied all the requirements of 37 C.F.R. .ANG..ANG.1.801-1.809, including providing an indication of the viability of the sample. Applicant imposes no restrictions on the availability of the deposited material from the ATCC; however, Applicant has no authority to waive any restrictions imposed by law on the transfer of biological material or its transportation in commerce. Inbred Corn Line PHTD5 is also a United States Protected Variety under Plant Variety Protection Certificate No. 9400095. Applicant does not waive any infringement of rights granted under this patent or the PVP Certificate.

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